Heli, the 'mirror image' is only a result of the arc(s) being drawn about the equator. The arcs are actually part of a Position Circle with one segment already eliminated by non reception by the adjoining satellite, and actually a second one (through Africa) outside the max range of a great circle track from the last radar fix, also eliminated.
The 'dots' would be the running fix on each later segment or arc, out from the centre, but note there would be two on any hourly range circle centered around each prior fix, being the circle intersect points along the next arc. Note that later arcs can be inside earlier arcs if the thing had done 180's. The area would actually grow in tree branch fashion.
The test of validity would be a feasible set of points along the final arc. Its a DR nav solution.
lakedude; look up 'running fix', with a radar fix near an early ping as a strart point.